The invention relates to methods and apparatus for manufacturing solid bodies, preferably of spherical or ring-shaped configuration, from a workpiece the material of which is removed in order to form the solid bodies. These workpieces preferably take the form of bars, plates, or blocks, and the workpiece is situated between a pair of tools which remove material from the workpiece to form a body of the above type therefrom.
Thus, the present invention relates to a method and apparatus for forming solid bodies of the above type by removing material from a workpiece with a pair of tools which are displaced toward each other while operating on the workpiece, these tools being displaced toward each other along a common axis.
With a method and apparatus of the above type spherical bodies, balls, rings, and the like are manufactured from a workpiece by removing material therefrom. Such a workpiece is preferably made of a suitable plastic, including foamed plastics, although it is also possible to utilize the invention in connection with workpieces made of natural or synthetic rubber, wood, ivory, or the like.
In connection with the state of the art, reference may be made to German Pat. No. 22,38,020, according to which a preferably square-shaped workpiece is rotated about a predetermined axis while material thereof is removed in order to form a circular surface. The tool which operates on this workpiece has an axis passing centrally and perpendicularly through the center of its cutting surface, and the rotation axis of the workpiece extends perpendicularly across this tool axis. The known apparatus disclosed in the above patent includes cylindrically shaped hollow cutting surfaces which are opposed to each other and which move toward each other while removing material from the workpiece. As a result of the above rotary movements with the above axes which are perpendicular to each other, a spherical body is formed from the workpiece, with material being removed from the workpiece at the end edges of the tools.
However, with this known method and apparatus it is always required that the workpiece be supported for rotation about a predetermined axis. This requirement of rotating the workpiece is extremely inconvenient and time-consuming, while at the same time as a result of this requirement there unavoidably remains at the finished body a through-passage or one or more openings necessitated by the structure for mounting the workpiece for rotation.